A fire in early October at Blue Ridge Fiberboard in Danville, Virginia, was caused by heat build-up in fibreboard stacked outside the plant, according to local fire authorities.

Assistant fire marshal Richie Guill said an investigation had found that heat built up over a period of days in the stacks of fibreboard. He added that the fibreboard was stacked tightly and wrapped in plastic and said the heat had continued to build until the boards reached their ignition temperature.

The fire caused moderate damage, affecting an exterior wall and a small office inside the building and destroying an estimated 100 pallets of fiberboard.

Blue Ridge Fiberboard published a notice to customers on its website stating that the Danville facility had experienced a minor fire in an outside storage and that operations and shipping were only curtailed for one day.